[wlesieutre]

Note that this behavior is OS specific. Windows will invert case (shift gives lowercase), while macOS will be all-caps (shift doesn't do anything).

Frankly I can't remember the Windows approach ever being useful to me, and more often than not it bites me in the ass because I habitually hit something like shift-i to type "I" and end up with a lowercase i instead.

[NamTaf]

Drafters (the guys who draw engineering drawings) love it because you very rarely but just enough have to type lowercase letters (such as units, like 3mm) whilst all other text must be in capitals. Thus, you just use shift to shift it to lowercase for those rare moments and no other times.